Beginnings of a performance testing suite.

Use `npm run benchmark`.

benchmark/compare-with-callbacks.js

@@ -0,0 +1,71 @@
+"use strict";
+
+var Q = require("../q");
+var fs = require("fs");
+
+suite("A single simple async operation", function () {
+    bench("with an immediately-fulfilled promise", function (done) {
+        Q().then(done);
+    });
+
+    bench("with direct setImmediate usage", function (done) {
+        setImmediate(done);
+    });
+
+    bench("with direct setTimeout(…, 0)", function (done) {
+        setTimeout(done, 0);
+    });
+});
+
+suite("A fs.readFile", function () {
+    var denodeified = Q.denodeify(fs.readFile);
+
+    set("iterations", 1000);
+    set("delay", 1000);
+
+    bench("directly, with callbacks", function (done) {
+        fs.readFile(__filename, done);
+    });
+
+    bench("with Q.nfcall", function (done) {
+        Q.nfcall(fs.readFile, __filename).then(done);
+    });
+
+    bench("with a Q.denodeify'ed version", function (done) {
+        denodeified(__filename).then(done);
+    });
+
+    bench("with manual usage of deferred.makeNodeResolver", function (done) {
+        var deferred = Q.defer();
+        fs.readFile(__filename, deferred.makeNodeResolver());
+        deferred.promise.then(done);
+    });
+});
+
+suite("1000 operations in parallel", function () {
+    function makeCounter(desiredCount, ultimateCallback) {
+        var soFar = 0;
+        return function () {
+            if (++soFar === desiredCount) {
+                ultimateCallback();
+            }
+        };
+    }
+    var numberOfOps = 1000;
+
+    bench("with immediately-fulfilled promises", function (done) {
+        var counter = makeCounter(numberOfOps, done);
+
+        for (var i = 0; i < numberOfOps; ++i) {
+            Q().then(counter);
+        }
+    });
+
+    bench("with direct setImmediate usage", function (done) {
+        var counter = makeCounter(numberOfOps, done);
+
+        for (var i = 0; i < numberOfOps; ++i) {
+            setImmediate(counter);
+        }
+    });
+});

benchmark/scenarios.js

@@ -0,0 +1,36 @@
+"use strict";
+
+var Q = require("../q");
+
+suite("Chaining", function () {
+    var numberToChain = 1000;
+
+    bench("Chaining many already-fulfilled promises together", function (done) {
+        var currentPromise = Q();
+        for (var i = 0; i < numberToChain; ++i) {
+            currentPromise = currentPromise.then(function () {
+                return Q();
+            });
+        }
+
+        currentPromise.then(done);
+    });
+
+    bench("Chaining and then fulfilling the end of the chain", function (done) {
+        var deferred = Q.defer();
+
+        var currentPromise = deferred.promise;
+        for (var i = 0; i < numberToChain; ++i) {
+            (function () {
+                var promiseToReturn = currentPromise;
+                currentPromise = Q().then(function () {
+                    return promiseToReturn;
+                });
+            }());
+        }
+
+        currentPromise.then(done);
+
+        deferred.resolve();
+    });
+});

package.json

@@ -51,11 +51,13 @@
     "promises-aplus-tests": "1.x",
     "grunt": "~0.4.1",
     "grunt-cli": "~0.1.9",
-    "grunt-contrib-uglify": "~0.2.2"
+    "grunt-contrib-uglify": "~0.2.2",
+    "matcha": "~0.2.0"
   },
   "scripts": {
     "test": "jasmine-node spec && promises-aplus-tests spec/aplus-adapter",
     "test-browser": "opener spec/q-spec.html",
+    "benchmark": "matcha",
     "lint": "jshint q.js",
     "cover": "cover run node_modules/jasmine-node/bin/jasmine-node spec && cover report html && opener cover_html/index.html",
     "minify": "grunt",